Oil burner control



Aug. 3, 1943. A. MAccHl on. BURNER comer.

original Filed Feb. 24, 1940 .n Figi Inventor. Ado Macch by` l isAttorrwqy.

l Patented Aug. 3, 1943 on. BURNEavcoN'rRoL Aldo Macchi, Belleville, N.J., assignor to General Electric Company, a corporation of New' YorkOriginal application February 24, 1940, Serial No. 320,557. Divided andthis application April 24, 1942, Serial No. 440,378

' 4. Claims.

The present invention relates to oil burners and the principal object isto provide an improved automatic combustion responsive control,particularly adapted for an electrically operated oil burner unit of theconversion type, so as to enable the unit to be readily applied tovarious types of furnaces or boilers.

This application isa division of my application Serial No. 320,557,filed February 24, 1940, which issued as Patent 2,311,404 on February16, 1943. A specific object is to provide an improved burner nozzle andcombustion responsive control construction whereby the burner nozzleand.

automatic controlparts can be built into a unit and interconnected incooperating relation thereby insuring thatthese parts of the unit workproperly together and facilitating the proper installation, andservicing of-the unit irrespective of the type of furnace or boiler towhich the unit is applied. u y

A more speciiicobject is to provide an improved oil burner` constructionhaving the nozzle and flame detector control parts, which must projectinto/.the furnace,.removab1y connected in proper operating relation withthe other parts. 'I'his improved structure` enables the burner nozzleheight to be readily'varied to conform with the height of the furnacedoor opening and alsou enables the control parts to be readilyaccessible for inspection, repairs,- removal or replacement, withoutdisturbing the lburner nozzle tube after it is once sealed in its properposition in the refractory walls of the furnace combustion chamber.

Another object of the invention is to provide an improved offset airinjection construction adjacent the end of the-conversion burnercombustionair discharge nozzle extending into the combustion chamber,whereby a quick and reliable response of the automatic ilame detectorcontrol is obtained without subjecting the temperature responsive partsto excessive or destructive temof the present invention; Fig. 2 is atopview partially in section of the oil burner unit shown in Fig-1; andFig. 3 is an end view of the burner nozzle showing the improvedlaterally oilset injector housing for the improved flame detector Asshown in Fig. 1, the conversion oil burner unit comprises a base I withthe adjustable legs II upon which base are mounted all of the principaloperating and control parts of the conversion oil burner unit includingthe electric motor driven air blower and air and oil pumping mechanismI2, the high voltage electric ignition transformer I3, the automaticstarting, stopping and sequence timing control mechanism I4 as well asthe complete burner air and oil discharge nozzle assemblage I5 includingthe main combustion air discharge nozzle I5a which is adapted to besealed into the refractory wall I6 of a boiler furnace or other type offurnace to which the conversion oil burner unit is applied and the oilatomizing nozzle 2| and other parts which are mounted inside of the main.nozzle I5a. The three supporting legs II are threaded into the baseI0.so as to bey independently adjustable, thereby permitting the entireburner nozzle assemblage I5 to be raised or lowered to the proper heightfrom the floor upon which the unit is mountedto conform with the furnacecombustlon chamber and also permitting leveling of the unit at thedesiredrheight. I'he base I 0' preferably is of pressed metal formedinto the shape supply means for the burner nozzle assemblage I5 andpreferably is of the improved type described and claimed in the LumPatent 2,032,291, granted FebruaryA 25, 1936, although any othersuitable type of combustion air blower and atomizing air and oil pumpingmeans may be provided for supplying the burner nozzle I5 with oil andcombustion air. The motor driven mechanism I2 preferably is resilientlymounted upon the base I0 by means of suitable springs I'I so as to avoidtransmission of noise and vibration to the base.

The electric ignition transformer I3 isshown sof-the conventional typewith its high voltage terminals I8 connected through suitable conlductors I9 to produce an arc between the two` oil streamdischarged'therefrom into the conicontrol part adjacent the end of thenozzle,

bustion air stream discharged from nozzle Ila. 'Ihe oil atomizing nozzle2| preferably is of the improved construction illustrated and describedin my Patent 2,249,482, granted July 15, 1941.

The proper energization of the ignition transformer Il, theelectromagnetically operated oil flow control valve 22, and also theelectric motor driven air and oil pumping mechanismv l2 from a suitablesource of electric power are under the control of a suitable oil burnertiming sequencing control switch mechanism I4 which may be of anydesired type although preferably it is of the type which is describedand claimed in the Eaton Patent No. 2,134,550 granted October 28, 1938;The various control details are well known in the art and are not deemedessential to proper understanding of the present invention and hence arenot shown other than the transfomer Ma for energizing the usual lowvoltage room thermostat, control circuits and the control motor Mb foroperating suitable sequencing cam switch mechanism for coordinating theenergization of the proper burner control circuits at proper times, inconjunction with the flame detector switch mechanism 50 which isdescribed in more detail hereinafter.

As shown in Figs. l, 2 and 3, the burner cornbustion air supply nozzle|5a preferably is moulded of cast iron and provided with sutablemounting lugs 25 so that it may be detachably mounted upon the uprightwall 26 which is suitably secured thereto as by spot welding and extendsupwardly from the right-hand end of the base I0. The removable jacket orenclosing casing 21 for the unit cooperates with the upright wall 26 toenclose all of the operating parts of the oil burner unit except thenozzle assemblage l5 on the outside of the wall. The upright wall 25 isprovided with suitable openings for receiving' the bolts 28 whichdetachably mount the main combustion air nozzle |5a. within which allthe other nozzle parts are mounted.

The upright wall 26 has suitable openings formed therein through whichextend the oil vascetic-l The upright wall 2.6 also is provided withanother suitable opening adjacent Athe top thereof supply pipe 29 andthe air supply pipe 30 which interconnect the inner oil of atomizingnozzle 2| with the air compressor and oil pump of the mo'- tor drivenmechanism I2. As shown, these oil and air supply pipes 29 and 30 extendthrough the nozzle tube 3| which is mounted along the axis of the maincombustion air nozzle |5a and adjacent the end of which the oilatomizing nozzle 2| is mounted. The nozzle tube 3| also carries thesupporting bracket 32 in which the ignition electrodes 20 are mounted inproper spaced relation with the atomizing nozzle 2| to effect ignitionof the atomized oil stream discharged therefrom. A suitable combustionair Whirler Jr spinner 33 is mounted upon the nozzle tube 3| with theends of the blades thereof extending into sliding engagement with theinterior of the combustion air nozzle |5a adjacent the discharge endthereof. Thus the spinner 33 serves to maintain the nozzle tube 3|centrally at the axis of nozzle |5a.

The oil and air supply pipes 29 and 30 are suitably secured to aremovable mounting plate 34 which is removably mounted in spaced apartrelation with the removable mounting plate 34a. to which tube 3| issecured so as to permit aA flow of air through the nozzle tube 3| frominside the enclosing jacket 2l due to natural draft and thus provide acooling action for the atomizing nozzle 2| after shut down of the burnerunit. Also, cooling during the running periods of the burner unit isobtained by allowing some fan air to enter the tube 3| through the noiesla which is located in tube 3| so that the air flow resistance (Fig. 1)oiered by the air spinner 33 will cause some combustion air to entertube 3| through hole 3|a.

for transmitting air under pressure from the motor driven blower 35 tothe inside of the enlarged offset scroll portion 36 of the combustionair nozzle I5. The pressure of the air supplied from blower 35 isregulated by means of a suitable adjustable damper 35a located adjacentthe blower inlet. As shown in Figs. 1 and 3, the enlarged offset scrollportion 35 of the air nozzle l5 forms in conjunction with the uprightwall 26 a flow directing chamber 36a for directing the combustion airflow downwardly and imparting a slight rotating motion thereto upon theentrance of the air under pressure to the nozzle l5. This enlargedOffset scroll portion `35 of the air nozzle I5 distributes thecombustion air coming from the blower 35 through chamber 36a so that itflows in equal amounts between the three equilaterally spaced iixedbaies 36h thereby improving the stability of the flame. The convergingaix-'discharge tip |5b of the combustion air nozzle |5 preferably ismade removable so that the tip |5b may be replaced whenever required as,for example, in case an extension of the air A and oil nozzles shouldbecome necessary for properly installing the conversion oil burner unitin a large size warm air furnace. The enlarged ofiset scroll portion 36of the air nozzle |5a serves to intercept much of the direct radiantheat from the furnace combustion chamber and transmit such heat to theair flowing into the air nozzle |5a thereby improving the combustionefficiency and at the same time preventing overheating of the operatingpart of the burner unit located behind the wall 26 within the enclosingjacket4 orcasing 21 closely adjacent the combustion chamber.

The air ow connection from the scroll housing of the blower 35 into thecombustion air inlet-'opening 3l formed in the upright wall 26preferably is made flexible and resilient by means of a suitable feltbushing 39 which is enclosed within the bushing mounting casing 39 whichin turn is removably mounted upon the upright wall 26 in any suitablemanner. The flexible felt bushing 38 prevents transmission of mechanicalvibration from the electric motor driven blower compressor mechanism |2to the wall 25 and also serves to prevent leakage of the air underpressure in its passage from the blower housing 35 into the flowdirecting chamber 36a.

Theupright wall 26 also is provided with a suitable opening for mountingthe detachable coupling 40 of the oil supply pipe 40a. Coupling 40 isconnected through the ilexible looped pipe 4| with the intake port 42 ofthe Oil pump embodied in the electric mo-tor driven oil and airmechanism I2.

With the improved conversion oil burner unit construction as abovedescribed it will be observed that all of the main operating parts ofthe burner are readily detachable from the cast iron air nozzle |5aafter it is once sealed in proper operating condition in the furnacecombustion chamber as illustrated in Fig. 1. By loosening the mountingbolts 28 and disconnecting the oil supply pipe 40a and the electricpower sup- 'ply and control cable 42, the entire unit includ-I bustionair nozzle I5. This-facilitates ready inspection, Kreplacement or repairof all of the operating parts of the burner unit. Furthermore, by merelylifting the enclosing jacket 21 which rests upon its bottom edge uponthe floor entirely independently of the main supporting base I0, all ofthe main essentia1 operating parts of the burner and control mechanismare made readily available for repair, adjustment or replacement.

As shown in Fig. 2', the opposing upright edges v 45 of the removableenclosing jacket 21 extend in overlapping sliding relation with theopposite side edges of upright wall 26. Thus when the base III isadjusted to its maximum height so as to bring the upper edge of wall 25into overlapping sliding engagement with jacket 21, as shown in Figf 1,then all combustion air is drawn into the blower air intake opening 35ainside of the enclosing jacket 21 after passing between the opposingupright edges 45 of the jacket 21 and under the base IU from therighthand side of the enclosing jacket closely adjacent the furnacecombustion chamber as indicated by the arrows in Fig. l. In case thebase Ill should be lowered so as to decrease the area of the air inletopening extending between the opposing upright edges 45 of the enclosingjacket 21 below the base I0, then an equivalent area of air inletopening is obtained above the top of the wall 25. Hence, the necessaryair inlet area into the jacket 21 is obtained irrespective of the heightat which the base IU is mounted. In any case, the air inlet opening intojacket 21 is directly adjacent the furnace combustion chamber so as todraw therein any heated air, fumes or products of combustion that may bereleased from the furnace. This location of the air inlet opening intojacket 21 also serves to suppress the transmission of noise from theinsideof the enclosing casing 21 to the surrounding atmosphere since anynoise vibrations which may pass through the air inlet opening areintercepted by the furnace.

Theimproved burner unit construction described above provides formaximum freedom in the construction, size and location of the variousessential elements of the burner air and oil supply and ignitionmechanism mounted upon the base Il) without interference with the othercooperating elements. Each main essential ele- 'ment may be separatelymanufactured in a standard form or size and mounted independently of theothers but in proper spaced and cooperating relation therewith. Thispermits sep-v arately improving and mounting of the several elements andfacilitates the final interconnection thereof in proper cooperatingrelation in the improved conversion oil burner unit. Any one of theVarious essential elements may be improved in structure with a minimumof interference with the other elements.

In the preferred form of the invention illustrated in the drawing, theautomatic burner control mechanism I4 is shown mounted directly upon theupright supporting wall 26 with the name responsive switch mechanism 50pref-V erably constructed as an integra-l part of the main automaticcontrol I4 and arranged to be responsive to combustion conditionsimmediately adjacent the end of the burner no-zzle.

It will be understood, however, that the flame responsive switchmechanism may be made a separate element from the main automaticsequencing control switch mechanism I4 if desired.

- the agency of the quartz rod 59 'combustion from the combustion In theform shown in Fig. 2 the flame responsive switch mechanism comprises abase vplate 5I to which is attached the supporting bracket 52 carryingthe pivoted switching arm 53 having the contact 54 carried at the endthereof between the two cooperating contacts 55 and 56. The pivotedswitch arm 53 is biased by spring 51 to engage contact 54 with thecontact 56 by means of the spring 51. The pivoted switch arm 53 isoperated against the bias of spring 51 by the sliding pin 58 which isconnected through which is relatively non-expansible upon temperaturechanges with the temperature responsive expansive tube ,60. 'I'hetemperature responsive expansive tube 60 preferably is formed ofnichrome or other suitable high temperature expansible material and ismounted at the end of the supporting tube 6I which in turn is supportedfrom the base plate 5I.

The burner combustion air nozzle I5 is provided with a special offsetinjector housing 15 extending from one side thereof adjacent thedischarge end of the chamber of the furnace. This special offsetinjector housing 15 is formed with a substantially U-shaped internalpassageway 15a with both ends of the U-shaped passage opening directlyinto the furnace combustion' chamber as indicatedl more clearly in Figs.2 and 3. In one leg 16 of this internal U-shaped passageway 15a, thetemperature responsive expansible element. 60 of the ame detector islocated. A small auxiliary air jet nozzle 11 .is connected with thelaterally offset scroll portion 36 of the combustion air supply nozzle I5 so as to admit a jet of air under pressure from the scrollv leg 18 ofthe U-shaped passage 15a. Thus the jet of air under pressure issuingfrom the nozzle 11 into the passage 18 sets up an injector action whichproduces a circulation of the products of vchamber through the U-shapedpassage itself and back again to thefurnaoe combustion chamber, asindicated by the arrows in Fig. 2. In this way a now of the products ofcombustion from the'furnace combustion chamber are drawn by the injectoraction set up by the auxiliary air nozzle 11 over the temperatureresponsive tube element 6U of the flame detector. `Thus the element 60although located entirely outside the furnace combustion chamber is madedirectly responsive to the temperature conditions produced by combustionin the furnace whenever the blower 35 is operating to supply air underpressure to the injector nozzle 11.

Whenever the oil burner unit is started'into operation by means of thesuitable automatic control mechanism I4 which ordinarily is under thecontrol of a room thermostat or other automatic condition responsiveJcontrol, oil and air will be supplied under pressure from the motordriven oil land air supply mechanism I2 to the burner atomizing nozzle2|. At the same time combustionair under lower pressure will be suppliedfrom the blower 35 tof'the inlet 31 of the combustion air nozzle I5.This flow of combustion air passes along and cools the outside of thenozzle tube 3| within which the oil atomizing nozzle 2 I is mounted.A1so,'a further cooling air now is drawn through the inside of thenozzle tube 3| directly over'the oil This cooling air flow through theinside of the nozzle tube 3| is jointly dependent upon the inthe blower`air flow at the tip of nozzle I5 and also upon the natural nozzle intothe combustion portion 36 into the other atomizing nozzle 2'I.`

ing air flow through the inside of nozzle tube 3I will continueindependently of the operation of blower 35 and prevent overheating ofnozzle 2| when the burner -unit is shut down. y

When the atomized oil stream issuing from the nozzle `2I is ignited fromthe electric arc established between the electrodes 20, combustionnormally will lbe established within the furnace combustionchamber. Thearcing electrodes 20 are energized from the high voltage terminals ofthe ignition transformer I3, the primary of which is suitably energizedduring theproper interval by the operation of the sequencing timingcontrol mechanism I4.

Due toth injector action produced by the auxiliary air nozzle 11, someproducts of combustion will be drawn from the furnace combustion'chamberover the temperature responsive expansible tube 60 thereby producing amovement of the flame responsive switch arm 53 to indicate the presenceof combustion in the combustion chamber. In case combustion shouldthereafter fail, the tube 60 will cool thereby reversing the operationof the switch arm 53 to indicate the absence of combustion. It will beunderstood that the flame detector switch 50 is connected to cooperatewith the burner control mechanism I4 so as to shut down the motordrivenoil and air supply means in case of combustion failure in themanner which is well known in the art. Likewise the flame detectorswitch 50 will cooperate with the control mechanism I4 to preventcontinued operatio-n of the motor driven compressor mechanism I2 in casecombustion is not established within a limited time interval after theburner unit is started into operation. This prevents accumulation ofunburned oil in the combustion chamber which might result in puiTs,explosions or other dangerous conditions.

With the improved conversion burner unit construction describedabove,the flame detector 50 and control mechanism I4 form an integral part ofthe unit and hence materially simplify the installation problem. All ofthe various cooperating parts may be properly mounted, interconnected inthe proper cooperating relation and tested together. Thus all that isnecessary for installation is to seal the burner air nozzle I5 in thefurnace combustion chamber and provide the necessary oil and electricpower supply and control connections to the unit.

What I claim as Anew and desire to secure by Letters Patent of theUnited States is:

1. An oil burner having, in combination, a combustion air dischargenozzle having air pressure supply means and jointly operable meansincluding an oil atomizng nozzle and an ignition means for producingcombustion adjacent the discharge end of said nozzle, an injectorhousing disposed adjacent the discharge end of said nozzle and having aninjector air jet means connected with said air pressure supply means forinducing a flow of the products of draft produced by the furnace. ,YHence the coolcombustion through said injector housing, and controlmeans including a temperature responsive element mounted in saidinjector housing in the path of the induced ilow of said products ofcombustion for controlling the operation of both of said jointlyoperable means.

2. In an oil burner, in combination, a burner combustion air discharge.nozzle having an oil atomizing nozzle and an ignition means mountedtherein adjacent the discharge end thereof, motor driven supply meansfor supplying oil and combustion air under pressure through said nozzlesto establish combustion, a U-shaped injector casing having the open endsthereof disposed adjacent the discharge end of said combustion airnozzle and provided with an injector air jet means connected with saidmotor driven combustion air supply means to discharge air under pressurethrough one leg of said U-shaped injector casing and thereby induce aflow of the products of combustion into the other leg of said U-shapedinjector casing, and control means including a switch having atemperature responsive operating element mounted in said other leg ofsaid U-shaped injector casing in the path of the induced flow of saidproducts of. combustion for controlling the operation of said motordriven supply means.

3. An oil burner having, in combination, combustion producing meansincluding a nozzle for discharging a combustible mixture of oil and air,said nozzle having an integral injector housing laterally oiset from thedischarge end thereof and provided with a U-shaped passage having theopen ends thereof disposed adjacent the discharge end of said nozzle,air jet means for discharging air under pressure through one leg of saidpassage toward the open end thereof to induce a return flow of theproducts of combustion into the other leg of said passage, and controlmeans including a temperatureresponsive element mounted in said injectorhousing in the path of the induced flow of said products of combustionfor controlling the operation of said combustion producing means,

4. An oil burner having, in combination, combustion producing meansincluding a horizontal- 1y projecting cylindrical combustion airdischarge nozzle tube provided With an internal axially disposed oilatomizing nozzle and an externally oiset U-shaped injector casing at thedischarge end thereof and with an enlarged air inlet casing at the otherend thereof having an auxiliary air jet nozzle extending therefrom fordischarging air from said air inlet casing into one leg of said U-shapedinjector casing to induce a return ow of the products of combustion intothe other leg of said casing, andmeans including a combustionVresponsive element disposed in said other leg of said injector casing inthe path of the induced ilow of said products of -combustion forcontrolling the operation of said combustion producing means.

ALDO MACCHI.

